In the LTE (including LTE-Advanced) mobile communication system, UE categories on capabilities of user apparatuses UE are defined, in which requirements that should be supported are different for each category. For example, DL/UL peak throughput and the supported number of MIMO layers are defined for each UE category. As an example, FIG. 1 (non-patent document 1: 3GPP TS36.306) shows DL capabilities for each UE category.
Also, in LTE, it is defined that the user apparatus UE sends a UE category of itself by a predetermined message “UE-EUTRA-Capability” when it connects to a network, for example (non-patent document 2: TS36.331).
In release-8 of 3GPP (to be referred to as Rel-8, hereinafter), fields for notification of UE categories 1-5 are defined in the UE-EUTRA-Capability message. In release 10 (to be referred to as Rel-10, hereinafter), UE categories 6-8 are additionally defined, and fields for notification of them are defined. More particularly, as shown in the underlined parts in an information element (IE) of UE-EUTRA-Capability shown in FIG. 2, fields for notification of UE categories 1-5 and fields for notification of UE categories 6-8 are defined.